From: Jussi Peltola <plz@plz.fi>
To: netdev@vger.kernel.org
Cc: "Bjørn Mork" <bjorn@mork.no>
Subject: [PATCH] Fixup packets with incorrect ethertype sent by ZTE MF821D
Date: Sun, 13 Nov 2016 15:47:53 +0200 [thread overview]
Message-ID: <20161113134753.GR2745@pokute.pelzi.net> (raw)
This brokenness appears reliably after running "rdisc6 wwan0" but I have
not debugged if this is related to timing or the format of the router
solicitation. Before receiving a router solicitation, v4 is received
correctly and v6 does not work. After sending the MF821D a router
solicitation with rdisc6, v4 is broken but v6 works. With this patch
(which I am using to write this message) a dual-stack context is usable.
commit 2c25237d19c0c9741c6ebec854def99b88618eac
Author: Jussi Peltola <plz@plz.fi>
Date: Sun Nov 13 15:41:50 2016 +0200
Fixup packets with incorrect ethertype sent by ZTE MF821D
Signed-off-by: Jussi Peltola <plz@plz.fi>
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 3ff76c6..edd8172 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -172,6 +172,12 @@ static const u8 buggy_fw_addr[ETH_ALEN] = {0x00, 0xa0, 0xc6, 0x00, 0x00, 0x00};
* Another common firmware bug results in all packets being addressed
* to 00:a0:c6:00:00:00 despite the host address being different.
* This function will also fixup such packets.
+ *
+ * At least the ZTE MF821D sends IPv4 packets with a bogus ethertype
+ * of 0x63bc, 0xe3bc, 0x63bd or 0xe3bd, and bogus source and
+ * destination MACs after it has received an IPv6 router solicitation
+ * (IPv6 is transmitted correctly). This function will also fix up
+ * such packets.
*/
static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
@@ -195,12 +201,21 @@ static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
return 0;
if (is_multicast_ether_addr(skb->data))
return 1;
+
/* possibly bogus destination - rewrite just in case */
skb_reset_mac_header(skb);
goto fix_dest;
default:
if (rawip)
return 0;
+
+ /* Bogus ethertype and src/dst mac for v4 on ZTE MF821D */
+ if ((skb->data[12] & 0x7f) == 0x63
+ && (skb->data[13] & 0xfe) == 0xbc) {
+ proto = htons(ETH_P_IP);
+ goto reset_mac;
+ }
+
/* pass along other packets without modifications */
return 1;
}
@@ -213,6 +228,7 @@ static int qmi_wwan_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
if (skb_headroom(skb) < ETH_HLEN)
return 0;
skb_push(skb, ETH_HLEN);
+reset_mac:
skb_reset_mac_header(skb);
eth_hdr(skb)->h_proto = proto;
eth_zero_addr(eth_hdr(skb)->h_source);
next reply other threads:[~2016-11-13 13:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-13 13:47 Jussi Peltola [this message]
2016-11-13 16:12 ` [PATCH] Fixup packets with incorrect ethertype sent by ZTE MF821D Bjørn Mork
2016-11-13 17:00 ` David Miller
2016-11-13 17:25 ` Jussi Peltola
2016-11-14 0:22 ` Jussi Peltola
2016-11-14 11:37 ` Bjørn Mork
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